Process fob producing certain oxi



Patented Dec. 31, 1935 PROCESS FOR PRODUCING CERTAIN OXI- DATION PRODUCTS OF CASTOR OIL AND Melvin De Groote, St. Louis, and Bernhard Keiser, Webster Groves, Mo., assignors to Tretolite Company, Webster Groves, Mo., a corporation of Missouri No Drawing. Application January 30, 1935,

Serial No. 4,092

Claims. (CI. 87-12) This invention relates to the manufacture of certain oxidation products of castor oil and the like, i. e., products obtained or produced by the oxidation of castor oil or castor oil bodies at a 3 relatively low temperature and at a pressure of not over 125 lbs.

The object of our invention is to provide a novel process for producing products or materials of the kind mentioned. Briefly described, our proco ess consists in subjecting castor oil or the like to pressure oxidation in the presence of an autooxidizer-catalyst consisting of a-cylvestrene-type, monocyclic, terpene body.

In order to clearly define and explain our. in-

vention, it will be necessary to refer briefly to prior processes or procedures that have been employed or suggested to obtain products or materials produced by the oxidation or blowing of various oils with dry or moist air or oxygen.

- In a general way, animal or vegetable oils may be divided into five general classes, based on their susceptibility to oxidation reactions, involving the use of air or omgen. Thefirst of the abovementioned classes includes such materials as flearic acid, which does not contain an. ethylene linkage and is not saturated. Such a fatty body s not susceptible to oxidation by the conventional methods.

The second of the above-mentioned classes is unique, in that the only material or materials of said class that are commercially available, are castoroil and simple castor oil derivatives, such as ricinoleic acid, or poly-ricinoleic acid. Castor oil is characterized by the fact that it may be exposed to air or oxygen for along time in a very thin film, without absorbing any oiwgen. In other words, notwithstanding. the fact that castor oil contains an ethylene linkage, still, so far as reactions at ordinary temperatures or pressures are concerned, it is hardly more reactive towards air or oxygen than if it were a saturated fatty body, such as stearin, or stearic acid.

The third of the above-mentioned classes of materials includes the so-called non-drying oils. These oils such as oleic acid, olein, etc. are nondrying in the sense that they do not absorb oxygen and dry quickly enough to produce a paint,

film. However, they are diiferentiated from castoroiLinthatafilmexposedtoairor oxygen at ordinary temperatures for a period of time, will oxidize slowly but rather completely.

The fourth of the above-mentioned classes of materials consists of the so-called semi-drying oils, such as cotton seed oil. and certain marine on: w"'ch are more reactive than oleic acid or the like, but not so reactive as the true drying oils, which are characterized, for example, by linseed oil.

The fifth of the'above-mentioned classes of materials comprises the true drying oils which 5 absorb air or oxygen rapidly enough to produce a paint film when exposed in a thin layer and which may absorb oxygen rapidly enough at ordinary temperatures to cause spontaneous combustion.

It is common practice to blow or oxidize various fatty materials of the kind above enumerated to produce materials intended for use in various arts. Linseed ofl, for example, is oxidized to produce a solid, such as linoxyn. Certain oils 1 are oxidized to produce plasticizers for use in the manufacture of artificial leather and the like. Certain oils are oxidized, so as to give miscibility with petroleum oils to produce blended lubricating oils. Certain oils are oxidized to produce a. product of certain desired characteristics employed in the manufacture of varnish and the like.

It is well known that an oxidation process or procedure, which may be suitable for one of the five general classes of oils, previously mentioned, may not be suitable for a difierent class. For example, the processes used to oxidize the linseed oil type of oil are-usually ineffective in regard to castor oil, or even in regard to oleic acid and the processes employed for oxidizing olive oil or rape seed oil, may be entirely too drastic for use on linseed oil. Moreover, in the oxidation of oils, particularly linseed oil, and certain marine oils, the

resultant product depends entirely on the mode of treatment. Marine oils, for example, may be oxidized primarily to decolorize or de-odorize the oil, and such oxidation is intended solely to oxidize or destroy the impurities so as to permit the oil under treatment to remain more or less unchanged.

. In the co-pending application for patent of the present applicants jointly with Arthur F. Wirtel. Serial No. 752,718, filed November 12, 1934, there is disclosed a process'for producing blown oils, that involves subjecting fatty bodies to oxidation after admixture with a relatively small amount of a vegetable oil of the true drying type, with or without a small amount of a fat splitting sulfonic acid.

In another co-pending application for patent filed by the above-mentioned applicants, Serial No. 760,031, filed December 31, 1934, there is disclosed a process for producing poly keto fatty bodies or poly aldehydic fatty bodies, that involves the oxidation of castor oil, polyricinohic or ricin- 'oleic acid under pressure at a relatively low temperature. The temperature employed in the said process is below the temperature at which castor is mixed with not over 20% of linseed oil. In

the absence of linseed oil, either the reaction does not take place, or the reaction takes place so slowly that such oxidation procedure would not be feasible nor economical, or might even produce some other compound. In a general way, oxidation of a mixture of 90% castor oil and 10% of linseed oil takes place very readily at a temperature of 120 C. and 45 lbs. air pressure. Such reaction may be completed in ten hours or less, depending upon the size of pressure vessel used during oxidation. The air employed may be dried or moist, in the sense that it may carry its normal moisture content.

Castor oil is differentiated from other oils and other fatty materials in regard to its reaction towards oxidation in various manners. As has been previously pointed out, castor oil, although containing an ethylene linkage, does not oxidize under ordinary conditions, even after long exposure in a thin film. For this reason it is even less reactive than ordinary so-called non-drying oils. Its action is more analogous, so far as oxidation goes, to inert oils of thestearic acid type. Castor oil or ricinoleic acid or the related esters, such as the ethyl, methyl, propyl, or butyl ester, are further distinguished by the fact that the materials contain an alcoholiform hydroxyl, and thus, ricinoleic acid is not only a fatty acid, but is also a fatty alcohol and is more properly described, perhaps, as an alcohol acid. Such materials which are characterized by the presence of a ricinoleic acid radical will be referred to as castor oil bodies because they are invariably derived from castor oil as an original raw material. It is a secondary alcohol, and, as is well known, the oxidation of a secondary alcohol produces a ketone, and thus, it is believed that the cautious oxidation of castor oil in the maner described in the saidDeGrooteet al. application Serial No. 760,031, results in the formation of keto acids or keto acid bodies, and particularly, in the formation of poly keto acid bodies. It is true that the fatty bodies thus obtained may actually be aldehydic fatty bodies and not keto fatty bodies, although both.

are characterized by a reactive carbonyl radical. We believe that the linseed oil present during the oxidation of castor oil, as described in the said De Grotte et al. application Serial No. 760,031, acts in part as an auto-oxidizer, and acts in part as an oxidation catalyst. Without attempting to elaborate as to the working mechanism of an auto-oxidizer (see "Catalysis in or ganic chemistry, Sabatier & Reid, 1923, pages 46 and 47), it is suflicient to state that an autooxidizer, in a general manner, oxidizes in proportion to its own mass, and it does not emerge unchanged from the reaction which it has caused. On the other hand, the addition of linseed oil, for

example, to castor oil, does not hasten the reaction directly in proportion to the added linseed oil. For instance, an -20 mixture .does not necessarily oxidize twice as rapidly as a -10 mixture. Furthermore, it is well known that some auto-oxidizers may be entirely regenerated and again serve as a carrier of free oxygen to the far as the commercial. operation of such oxidation reactions are concerned, it is obvious that these materials may be added in the designated proportion and the mixture submitted to oxidation under the. described conditions, so as to obtain the advantages described, without reference as to the theoretical aspects of the oxidation step itself.

We have found that while certain materials,.-

will act as auto-oxidizer-catalysts, so as to pro; mote the cautious and controlled oxidation of castor oil or the like at relatively low temperatures and under moderate pressures of the kind described, there does not appear to be any general characteristic whereby this particular property of a substance may be anticipated. Materials which may serve as auto-oxidizers or catalysts in regard to other reactions may not have any eflect in hastening the oxidation of castor oil under the described conditions. Likewise, materials which may be effective in hastening the oxidation of castor oil, under the conditions described, may not be effective in other reactions where it is known that some other auto-oxidizercatalysts may be employed. At least, at the present time and in regard to the low temperature pressure oxidation of castor oil bodies, it appears that this peculiar property is that of an individual substance or compound, and cannot be ascribed to a class broadly, as far as we are now aware.

We have found that the monocyclic terpenes of the sylvestrene-type are very effective auto- 5 oxidizer-catalysts, when employed in low temperature pressure oxidation of castor oil bodies. The sylvestrene-type of monocyclic terpenes, as stated in the publication Text Book of Organic Chemistry, Bernthsen, 1931 edition, pages 61'! CH3 CH3 OH;

H n H H H H I a n m H H, H] H HI I C1117 C(CHa): HrO=OHl Fourteen such isomerides are theoretically possible. The carbon atoms are usually numbered as follows: 09 1cl 2 3 4 o The above materials may also be referred to as the menthadiene type of monocyclic terpenes. Reference is made to the following statements, which appear in A Text Book of Organic Chemistry, by Schmidt, 1932, pages 464, 5 and 6:

"Terpenes are cyclic hydrocarbons of the formula (Cd-Is), and occur widely distributed in nature. Hydrocarbons-of this group are generally subdivided into hemi-terpenes, CsHs; terpenes, CIOHIS; etc. The terpenes C1oH1e,aI'e all unsaturated hydrocarbons containing either one or two ethylene bonds in the molecule, according to which they are again dividedas follows:

1. Monocyclic terpenes containing two double bonds. These are dihydro-cymenes, and may therefore be regarded as partially reduced benzene derivatives. Included in this class are limonene (dipentene), sylvestrene, terpinene, and terpinolene. (Phellandrene is also included in the class on page 467). Tetrahydro-cymenes are therefore described as menthanes and dihydro-cymenes as menthadienes.

Thus, if one prefers the six materials previously referred to, they may be designated as monocyclic terpenes of the'menthadiene type.

It is convenient to refer to this class as the sylvestrene class, because sylvestrene is a naturally-occurring constituent of- Swedish and Russian oil of turpentine and its composition has been the source of considerable investigation. It is obvious that one might obtainsozne simple derivative of these various substances which did not materially affect the-structure, for instance, a chlorine substitution product of the kind which still contained the two unsaturated bonds and which, for all practical effect, would'be just as valuable as an auto-oxidizer-catalystI as the original hydro-carbon itself. In practising our process we prefer to use dipentene, because it can be obtained readily from turpentine or other similar materials and is available in the open market at a relatively low cost. In our process we use not over 20%, and preferably, approximately 10% of a sylvestrene-type monocyclic terpene body, preferably, dipentent, as an auto-oxidizercatalyst in the low temperature pressure oxidation of castor oil, so as to produce oxidation 5 products of the kind which appear to be poly keto or poly aldehydo fatty bodies. We preferthat the oxidation be conducted with air having its ordinary moisture content and at a temperature of C. and at a gauge pressure of 45 lbs. 10

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A process for the purpose described, characterized by substantially oxidizing castor oil at 35 a temperature within the range of approximately 120 C. to 150 C. and at a gauge pressure within the range of 25 lbs. to lbs., and using 10% to 20%, by weight, of dipentene as an autooxidizer-catalyst.

2. A process for the purpose described, which consists in substantially oxidizing castor oil by means of air of normal moisture content at a temperature within therange of approximately 125 C. to C. and at a gauge pressure within 2 5 the range of 25 lbs. to 125 lbs., and using 10% to 20%, by weight, of dipentent as an auto-oxidizercatalyst.

3. A process for the purpose described, which consists in substantially oxidizing castor oil by 30 means of air of normal moisture content at a temperature of approximately 120 C. and under a gauge pressure of 45 lbs., and using as an autooxidizer-catalyst dipentene, equivalent in weight to 10% of the castor oil being oxidized. 35

4. A process for the purpose described, characterized by substantially oxidizing, by means of a gaseous, oxygen-containing medium, a castor oil body at a temperature within the range of approximately 120 C. to 150 C., and at a gauge 40 pressure within the range of 25 lbs. to 125 lbs. and using 10% to 20%, by weight, of a monocyclic terpene of the formula C10Hl6 as an autooxidizer-catalyst, .said castor oil body being characterized by the presence of a ricinoleic acid 45 radical.

5. Aprocess for the purpose described, characterized by substantially oxidizing, by means of a gaseous, oxygen-containing medium, castor oil at a temperature within the range of approxi- 50 mately 120 C. to 150C. and at a gauge pressure within the range of 25 lbs. to 125 lbs. and using 10% to 20%, by weight, of a monocyclic terpene of the formula CmHw as an auto-oxidizercatalyst. 55

MELVIN DE GROOTE. BERNHARD KEISER. 

